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Which is the Best Boiler for my Budget?

Are you looking to buy a new boiler? There is a lot to consider, but we have made it easy for you find your ‘best boiler’. Read our handy guide to buying the right boiler for your circumstances.

Industry ‘Best Buys’

There are some great reviews on the best boilers to buy from Which? and other consumer websites. However they tend to concentrate on a single product from a boiler manufacturer’s range of boilers.

Your Best Buy

We think finding the best boiler is more individual than industry best buys. The best boiler to buy will depend on:

1) Which boiler you have currently
2) Your requirements for the new heating system
3) Your property size
4) Your budget

Using this Guide

We have designed this guide so you can find your best boiler in four steps:

1) Identify your current system - do you have a combi, system or regular boiler (including back boilers)?

Combination Boilers

A combi boiler combines heating and hot water production in a single unit. No need for water tanks.

Heat only boiler (regular boiler and back boilers)

A regular or heat-only boiler provides heating directly to the radiators and hot water via a cylinder. These are often open vented system which means you’ll have tanks in the loft. A back boiler is a form of heat only boiler but it is located in the fireplace.

System boiler

A system boiler is also a heat only boiler and works with an unvented hot water cylinder. The main difference between a regular and system boiler is the components found externally on a regular boiler are integral on a system boiler.

2) What are your requirements for the new system?

There are three types of boiler installation:

Boiler swaps - keeping the same boiler in the same location

If you have an existing combi, regular or system boiler and you are happy with its performance then the most cost effective solution is to retain that system in its original location.

NB for regular boilers, the manufacturer’s boiler warranty will only cover the boiler – the cylinder and other external heating elements will not be covered. These will be subject to on going maintenance and replacement costs.

Boiler moves - moving the boiler but keeping the same boiler type

If you want to move the boiler, from say a kitchen cupboard to the loft, you will need a gas safe engineer to check the suitability of the existing gas pipe.​

The installation will also cost more money because the fitting time will be 1.5 – 2.5 days instead of one day for a ‘boiler swap’ in the same location.

Boiler changes - changing the boiler type - in the same or new location

If your circumstances change or you just want to free up space, you can change your boiler type, the most common changes are as outlined below:

Regular boiler to combi boiler

If you want to move from a regular boiler system to a combi boiler then there are advantages and disadvantages to consider:

You will have more space by freeing up the airing cupboard

You will have lower maintenance costs as heating and hot water functions are integral to the boiler and covered by the manufacturer’s warranty

Instant hot water

Avoid if you have poor water pressure or flow rates

Avoid if you have three or more bathrooms

Avoid if you have old radiators

More expensive than a ‘boiler swap’ of the same type in the same location

CHECK the gas pipe run and size - it will likely need a larger gas pipe

Regular boiler to a System boiler

If you are keeping your heat only boiler, then it is worth considering installing a system boiler instead of another regular boiler:

Installing a system boiler will improve the manufacturer’s boiler cover. With more of the components integral to the boiler and covered by the manufacturer’s warranty, your long term maintenance costs will be lower.

You will need to upgrade your hot water tank to an unvented cylinder which is additional cost.

Combination boiler to a System boiler

You would probably only consider this system change if you are extending your property and adding bathrooms

The hot water flow rates on even the biggest combi boilers are reduced when there are multiple bathrooms and hot water taps in use at the same time

You will need to add an unvented hot water tank

Upgrading your back boiler

A back boiler is type of regular boiler found in the fireplace. It is no longer possible to replace a back boiler in its existing location.

Your options are to either to retain the hot water cylinder and install a regular boiler elsewhere in the property, such as the kitchen or the loft.

Or you can remove the hot water cylinder along with the back boiler and install a combi boiler, providing your water pressure is sufficient.

The cheaper option is to retain the hot water cylinder and just install a regular boiler elsewhere.

However the same disadvantages apply with regard to manufacturer’s boiler cover etc – see 'Regular boiler to Combi boiler' under this section.

3) Find your property size

The tables below are arranged by boiler type - combi, regular or system - and then by property size. Find your boiler type and then your property size.